Added IsometricStaggeredTiledMapRenderer for GWT
Added IsometricStaggeredTiledMapRenderer

Based of IsometricTiledMapRenderer.
For more info see:
http://gamedev.stackexchange.com/a/49848
http://legendofmazzeroth.wikidot.com/staggered-isometric-maps
Merge pull request #729 from semtiko/master

Added IsometricStaggeredTiledMapRenderer